Here are some of the tools I developed over the years, mostly during my life as a researcher.

Radian

Radian
is a tool for the visualization of traceroute measurements.
It presents the network at different abstraction levels
and allows to animate the evolution of network paths during a selected time interval.

BGPlay.js is a Web-friendly reimplementation of a popular tool called BGPlay.
It helps visualize changes to the reachability of any IP subnet,
based on BGP updates collected at various world locations.

VisualK allows to visualize the status and evolution
of the service provided by the
K-root name server
in near real-time.

K-root is pictured as a node-link graph where each node is an
anycast instance and each link implies topological
proximity between two instances. The size of each node reflects
the volume of traffic served by the corresponding instance.
Links become active when there are traffic migrations between instances.